योगवासिष्ठः yogavāsiṣṭhaḥ - book-6, chapter-81, verse-81

जन्माङ्गबीजाङ्कुरवत्तथा दिवसरात्रिवत् ।
स्थितिश्छायातपसमा केवला सैतयोर्भवेत् ॥ ८१ ॥

janmāṅgabījāṅkuravattathā divasarātrivat ,
sthitiśchāyātapasamā kevalā saitayorbhavet 81

81. janmāṅgabījāṅkuravat tathā divasarātrivat
sthitiḥ chāyātapasamā kevalā sā etayoḥ bhavet

81. janmāṅgabījāṅkuravat tathā divasarātrivat
etayoḥ sthitiḥ chāyātapasamā sā kevalā bhavet

81. Their existence is like the relation between birth, component, seed, and sprout, and like day and night; for these two (Agni and Soma), their state (sthiti) is singularly comparable to that of shadow and light.

Words meanings summery:

• जन्माङ्गबीजाङ्कुरवत् (janmāṅgabījāṅkuravat) - like the sequence/interdependence of birth, limb/component, seed, and sprout (like birth, limb, seed, and sprout)

• तथा (tathā) - and, similarly (thus, so, and, in that manner)

• दिवसरात्रिवत् (divasarātrivat) - like the alternation of day and night (like day and night)

• स्थितिः (sthitiḥ) - their current state or existence (state, condition, existence, position)

• छायातपसमा (chāyātapasamā) - comparable to the interplay of shadow and light (similar to shadow and light)

• केवला (kevalā) - singularly, unique to them (singular, unique, isolated, mere)

• सा (sā) - that (state) (that, she)

• एतयोः (etayoḥ) - for these two (Agni and Soma) (of these two, for these two)

• भवेत् (bhavet) - it should be (understood as) (it would be, it should be)

Words meanings and morphology

जन्माङ्गबीजाङ्कुरवत् (janmāṅgabījāṅkuravat) - like the sequence/interdependence of birth, limb/component, seed, and sprout (like birth, limb, seed, and sprout)

(indeclinable)

Suffix 'vat' appended to a dvandva compound.

Compound type : dvandva (janman+aṅga+bīja+aṅkura)

• janman – birth, origin, existence
  noun (neuter)
  Root: jan (class 4)
• aṅga – limb, body, component, constituent part
  noun (neuter)
• bīja – seed, origin, cause
  noun (neuter)
• aṅkura – sprout, shoot, germ
  noun (masculine)
  Root: ank (class 1)

तथा (tathā) - and, similarly (thus, so, and, in that manner)

(indeclinable)

दिवसरात्रिवत् (divasarātrivat) - like the alternation of day and night (like day and night)

(indeclinable)

Suffix 'vat' appended to a dvandva compound.

Compound type : dvandva (divasa+rātri)

• divasa – day
  noun (masculine)
• rātri – night
  noun (feminine)

स्थितिः (sthitiḥ) - their current state or existence (state, condition, existence, position)

(noun)

Nominative, feminine, singular of sthiti

sthiti - standing, position, state, condition, existence, firmness

Derived from root sthā

Root: sthā (class 1)

छायातपसमा (chāyātapasamā) - comparable to the interplay of shadow and light (similar to shadow and light)

(adjective)

Nominative, feminine, singular of chāyātapasama

chāyātapasama - like shadow and light

Compound type : tatpurusha (chāyā+ātapa+sama)

• chāyā – shadow, shade, reflection
  noun (feminine)
• ātapa – sunlight, heat, sunshine
  noun (masculine)
  Prefix: ā
  Root: tap (class 1)
• sama – equal, similar, like
  adjective (masculine)

केवला (kevalā) - singularly, unique to them (singular, unique, isolated, mere)

(adjective)

Nominative, feminine, singular of kevala

kevala - alone, solitary, mere, unique, pure, uncompounded

सा (sā) - that (state) (that, she)

(pronoun)

Nominative, feminine, singular of tad

tad - that, it, she, he

एतयोः (etayoḥ) - for these two (Agni and Soma) (of these two, for these two)

(pronoun)

Genitive, masculine, dual of etas

etas - this, these

भवेत् (bhavet) - it should be (understood as) (it would be, it should be)

(verb)

3rd person , singular, active, optative (vidhi liṅ) of bhū

optative active

root 'bhū', optative 3rd person singular

Root: bhū (class 1)